JavaScript: Types of Variables

In JavaScript, variables are used to store and manipulate data. JavaScript is a dynamically typed language, meaning you don't need to specify the data type of a variable explicitly; the type is determined at runtime. There are several types of variables in JavaScript, and they can be broadly categorized into the following:

 

1. Primitive Data Types:

   • Number: Represents numeric values (integers or floating-point).

     let num = 42;       // integer
     let floatNum = 3.14; // floating-point

   • String: Represents textual data.

     let str = "Hello, World!";

   • Boolean: Represents true or false values.

     let isTrue = true;
     let isFalse = false;

   • Null: Represents the intentional absence of any object value.

     let nullValue = null;

   • Undefined: Represents the uninitialized or undefined value.

     let undefinedValue;

   • Symbol: Introduced in ECMAScript 6, symbols are unique and immutable primitive values, often used as unique identifiers.

     let sym = Symbol("unique");

2. Object Data Type:

   • Object: Represents a collection of key-value pairs and is a fundamental data structure in JavaScript.

     let person = {
       name: "John",
       age: 30,
       isStudent: false
     };

3. Special Data Types:

   • BigInt: Introduced in ECMAScript 2020, BigInt is used for representing arbitrarily large integers.

     let bigNum = 123n;

4. Reference Data Types:

   • Array: Represents an ordered collection of values.

     let numbers = [1, 2, 3, 4, 5];

   • Function: Functions are objects in JavaScript, and you can assign them to variables.

     let add = function (a, b) {
       return a + b;
     };

   • Date: Represents a date and time.

     let currentDate = new Date();

   • RegExp (Regular Expression): Represents a regular expression pattern.

     let regex = /[a-zA-Z]+/;

 

 

These are the basic types of variables in JavaScript. Understanding these types is crucial for effective programming in the language. Keep in mind that JavaScript is a dynamically typed language, so a variable's type can change during runtime.

 

Thank you.